1. Field of the Invention
The present invention relates to a fuel tank cap adapted to prevent the back flow of fuel in a collision of "roll-over" of the vehicle. More particularly, the invention relates to a tubular-shaped tank cap which is securable to the gas door or cover for the opening for the fuel tank filler neck. This tank cap encloses a safety chamber preventing "back flow" when the cap is in place.
2. Description of the Relevant Art
A number of devices have been developed to control the release of fuel which may result from a vehicular accident. These prior fuel caps generally include a roll-over safety valve which operates on pressure-vacuum conditions.
U.S. Pat. No. 4,830,067 discloses a guard to prevent splashing of fuel while refilling a fuel tank. The guard comprises a flexible baffle attachable to a fuel neck cover which permits a gas nozzle to pass through an opening. However, the guard would not prevent release of fuel in a "roll-over" accident.
U.S. Pat. No. 4,784,423 discloses a filler cap including an outer door which matches the contour and color of the vehicle. In use, the cap and outer door are removed during refilling.
U.S. Pat. No. 4,716,920 discloses a fuel cap having a roll-over safety valve which closes upon inverted orcentation of the valve preventing fuel release.
U.S. Pat. No. 4,787,529 discloses a fuel cap utilizing liquid and vapor in filler neck to exert closing force on the pressure relief valve to prevent inadvertent release of fuel.
U.S. Pat. No. 4,768,677 discloses a fuel cap with a top portion adapted to release from a "stopper" portion situated within the filler neck to prevent release of fuel in an accident.
The present invention provides an improved gas filler neck cap which prevents back flow of fuel in an accident without relying on vapor pressure.